Oligocene-Miocene (28–13 Ma) climato-tectonic evolution of the northeastern Qinghai-Tibetan Plateau evidenced by mineralogical and geochemical records of the Xunhua Basin
9
Citation
108
Reference
10
Related Paper
Citation Trend
Keywords:
Aridification
Halite
Illite
Tectonic uplift
W artykule przedstawiono wyniki badan rentgenostrukturalnych i derywatograficznych mineralow ilastych z utworow triasu gornego monokliny śląsko-krakowskiej. W osadach kajpru wystepują zespoly: chloryt, illit i illit-smektyt oraz illit, chloryt i illit-smektyt, natomiast w osadach retyku zespoly: illit-smektyt, chloryt i illit oraz illit, kaolinit, illit-smektyt i ślady chlorytu. Zawartośc chlorytu wzrasta ku osadom starszym, zaś kaolinitu, wystepującego tylko w utworach bezwapiennych, ku osadom mlodszym. CLAY MINERALS IN THE UPPER TRIASSIC SEDIMENTS IN ENVIRONS OF KLUCZBORK The mineral composition of the clay fractions of the Upper Triassic sediments, which are under exploitation in the environs of Kluczbork, the Silesia-Krakow monocline, has been analysed by X-ray and DTA methods. They are composed mostly of the following clay minerals: illite, irregularly interstratified minerals of the illite-smectite series and chlorite. Kaolinite is usually lacking. It appears only in the limeless sediments of the Rhaetic. In the Keuper, two different assemblages of clay minerals are present: chlorite, illite, irregularly interstratified illite-smectite and illite, chlorite irregularly interstratified illite-smectite. They differ from the assemblage comprising kaolinite, illite, irregularly interstratified illite-smectite and traces of chlorite, which is characteristic for the Middle Triassic sediments. In the Lower Rhaetic, irregularly interstratified illite-smectite prevails over ,chlorite and illite. The Middle Rhaetic sediments yield illite, irregularly interstratified illite-smectite, chlorite and kaolinite. The mineral ratios are changed again in the uppermost Rhaetic sediments yielding the following series: illite, kaolinite, irregularly interstratified illite-smectite and traces of chlorite. Chlorite is represented by clinochlore-like clay mineral and its content increases along with the age of the layers. Illite has a clearly dioctahedral disordered structure and may be classified as Md polytype. It is associated by the swelling-faze of the various content, from 20 volume per cent in the old layers, up to about 90 volume per cent in the youngest layers of the Triassic. The minor constituents of the clay fractions in the Triassic sediments are the following accessory minerals: quartz, calcite, dolomite and anatase.
Illite
Cite
Citations (1)
Crystals of dioctahedral illite and chlorite occur in tonsteins associated with upper Permian coals of semi-anthracite rank in the Bowen basin, Queensland, whereas kaolinite is absent. It is inferred that the chlorite and illite were formed by replacement of kaolinite. Some minor illite (2M), twinned albite, and chlorite of detrital origin are also present. The chlorite-dioctahedral illite assemblage is related to the rank of the associated coals. Persistence of kaolinite in tonsteins of other high-rank coals is ascribed to compositional factors.
Illite
Anthracite
Coal rank
Cite
Citations (20)
Three types of clay mineral assemblage were identified in surface sediments from the Chukchi Sea and Canadian Basin,among them,the illite-kaolinite-chlorite-smectite assemblage was found only in the northern Canadian Basin,the illite-chlorite-smectite-kaolinite assemblage was mainly found in the central Chukchi Sea,and the illite-chlorite-kaolinite-smectite assemblage is widely distributed in the rest part of the study area.Generally,the illite and kaolinite contents show an increasing trend from the Chukchi Sea toward the Canadian Basin,and the chlorite and smectite contents show a decreasing trend.If taking the line connecting point(74°30′N,175°W) and point(71°30′N,150°W) as a demarcation line,the study area can be divided into two clay mineral provinces,the south province and the north province,the south pro-vince is characterized with higher contents of chlorite and smectite,higher ratios of S/I and S/K and lower ratios of K/I and K/CH;and the north province is characterized with higher contents of illite and kaoli-nite,lower ratios of S/I and S/K and higher ratios of K/I and K/CH.It is shown from the clay mineral distributions and variational trends that the clay mineral sources and the factors controlling their distributions in the south province and the north province are different from each other.The clay minerals in the south province are derived mainly from the weathering products of Alaska's rocks and the sediments delivered by the Yukon River and the rivers along the coast of the East Siberian Sea,and the clay mineral distributions in the south province are controlled mainly by the Siberian Coastal Current and the flowing structure of the Pacific Water entering into the Arctic Ocean;and the clay minerals in the north province are derived mainly from the sediments delivered by the Mackenzie River of Canada and the fine-grained sediments dispersed from the Eurasian Basin of Arctic Ocean,and the clay mineral distributions in the north province are controlled mainly by the Transpolar Drift,the flowing structure of Atlantic Water and the Beaufort Gyre in the Arctic Ocean.
Illite
Parent rock
Cite
Citations (1)
Abstract The micro‐nano pore structure of conglomerate in the Lower Karamay Formation of the Xinjiang Oilfield, Junggar Basin, northern China is characterized to predict its impact on fluid reserves and seepage. Authigenic clay minerals are mainly kaolinite (67%), followed by an illite/smectite mixed layer (18%), illite (10%), and chlorite (5%). For kaolinite, pore throats between 0–200 nm are dominant, accounting for 90% of the total pore throats. For illite/smectite mixed layer, pore throats also between 0–200 nm account for nearly 80%, while pore throats between 200‐500 nm only account for 15%. For illite, pore throats below 100 nm account for about 80%, while pore throats in the range of 100–500 nm only account for 20%. For chlorite, most throats are below 200 nm. The pore roundness of illite is the highest, while the pore roundness of chlorite is relatively lower. The lower limits of the dynamic and static pore throat radii are 42.128 nm and 72.42 nm, respectively. The theoretical contribution rates of the illite/smectite mixed layer, kaolinite, illite and chlorite to storage/seepage are 60%/45.86%, 52.72%/38.18%, 37.07%/28.78% and 32.97%/26.3%, respectively. Therefore, the contribution rates of clay minerals in the study area are as follows: illite/smectite mixed layer, kaolinite, illite and chlorite.
Illite
Authigenic
Conglomerate
Cite
Citations (9)
Illite
Sequence (biology)
Cite
Citations (47)
Abstract Diagenetic chlorite is forming as a result of temperature-controlled burial diagenesis in shales from the Sleipner area of the North Sea. Accompanying chlorite diagenesis, kaolinite and illite-smectite decrease in abundance, and illite increases in abundance. These clay mineral transformations occur between 122–126°C at temperatures higher than normally expected for chlorite diagenesis. Kaolinite and ordered illite-smectite are largely unaffected by diagenesis below 100°C. It is proposed that chlorite diagenesis is thus delayed due to the absence of a source of ions resulting from smectite decomposition. Clay mineralogy is of no lithostratigraphic use in the Jurassic sediments of the Sleipner area. However, the zone of chlorite diagenesis is a reliable indicator of maximum burial temperature.
Illite
Cite
Citations (17)
Based on the previously available data of clay minerals in the surface sediments of the Southern Yellow Sea,this paper mainly deals with the distribution of 4 types of the clay minerals(illite,kaolinite,smectite and chlorite).The research results show that the content of the illite in this area is the highest,the smectite or kaolinite are the second and chlorite is the lowest;the illite-smectite-kaolinete-chlorite-type rock is the main type of the clay minerals assemblage in the area,and the second one is illite-kaolinete-smectite-chlorite-type;the material source of clay mineral is mainly from the Yellow River and theYangtze River.
Illite
Cite
Citations (5)